1. Field of the Invention
The present invention relates to a technique of sequentially supplying process gases in a film deposition apparatus, which mutually react, by revolving substrates using a turntable to thereby laminate reaction products on a surface of the substrate and deposit a silicon dioxide.
2. Description of the Related Art
As one method of depositing a thin film such as a silicon dioxide film (SiO2) on a semiconductor wafer (hereinafter, referred to as “wafer”), an Atomic Layer Deposition (ALD) method is known. According to this ALD method, a plurality types of process gases (reaction gases), which mutually react, are sequentially supplied on the surface of a wafer to thereby laminate reaction products. Japanese Laid-open Patent Publication No. 2010-245448 discloses a film deposition apparatus, with which a film is deposited by the ALD method. The film deposition apparatus is structured such that a turntable, on which a plurality of wafers are mounted so as to be arranged in a peripheral direction, is provided, and a plurality of gas nozzles is arranged so as to face the turntable. For example, the process gas is, for example, a gas containing silicon (Si) such as bis(tertiary-butylaminosilane) (BTBAS) gas and an oxidation gas such as an ozon (O3) gas. A film deposition process is performed by revolving the turntable relative to the gas nozzle while heating the wafers using a heater provided on a lower side of the turntable. With this, the Si containing gas and the ozone gas are sequentially supplied to the wafer. Thus, a reaction is performed to oxidize the Si containing gas using the ozone gas. Then, a SiO2 film is formed.
It is anticipated that high denseness is required depending on a portion of a semiconductor device, to which a SiO2 is applied. In order to obtain such a SiO2 film, it is necessary to perform the reaction at a high temperature exceeding, for example, 650° C. However, if a film deposition apparatus causing the wafers W to orbitally revolve with the turntable is used, a heat-resistant structure of the sealing portion for maintaining a vacuum atmosphere is not easily obtainable. Further, because the gas nozzle provided on an upper side of the turntable is heated by heat of the turntable, if the turntable exceeds 650° C., the temperature of the gas nozzle is increased. Therefore, the internal temperature of the gas nozzle exceeds the temperature of 550° C., at which the ozone gas is thermally decomposed. Therefore, before the ozone gas reaches the turntable, the ozone gas is thermally decomposed into oxygen. Therefore, oxidation power of the ozone gas is reduced, and such an ozone gas cannot be used as an oxidation gas. Therefore, if a film deposition apparatus, which has special specifications and is different from a type using an ozone gas, is to be manufactured, the manufacturing cost of such a film deposition apparatus becomes high.
Japanese Laid-open Patent Publication No. 2010-245448 discloses a structure in which a heater unit is provided on the lower side of the turntable, and a rod-like infrared lamp is additionally provided on the upper side of the turntable.